How much methane is emitted into the atmosphere each year due to steel making? The answer, surprisingly, seems to be that no one really knows. To date, estimates of steel’s methane emissions have focussed on the sector’s use of ‘metallurgical coal’. Metallurgical coal includes various grades of coal used for coke making (‘coking coal’), as…

So the steel sector emits around 3.7 gigatonnes (Gt) of carbon dioxide (CO2) a year (see ‘6%, 7%, 8%, 9%, 10%, 11%…’), and perhaps another 18.3 million tonnes (Mt) of methane (see ‘Steel’s methane footprint’). But the GHG Protocol lists five more greenhouse gases or groups of gases: nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur…

A few months back I tried to get to the bottom of the wide range of statements about the steel sector’s CO2 emissions. The answer was that the production of crude steel is responsible for emitting around 3.7 Gt of CO2 – 8% to 10% of human emissions (see: ‘6%, 7%, 8%, 9%, 10%, 11%…’). But…